| 摘要 |
A system for quickly and easily making accurate purity and yoke adjustments of a color cathode ray tube of a television receiver utilizes a separate oscilloscope display of vector beam landing errors. Photocells, provided with filters to cause them to be responsive to selected colors, are placed in front of the cathode ray tube to produce output pulses once for each vertical scan of the beam in the cathode ray tube. A rotational beam landing shift at 15 Hertz is produced by a vertical and horizontal deflection field generated in synchronism with the vertical deflection signal of the cathode ray tube to cause a stepped deflection of the beam in a diamond pattern of up, right, down and left for each successive vertical field. Light variations sensed by the photocell pickup are converted to a 15 Hertz signal which is combined with a 15 Hertz reference signal to control the dot location on the oscilloscope display of the vector beam landing error. Purity adjustments and yoke adjustments then are made on the cathode ray tube by observing the oscilloscope display.
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